Novel Simulation Model for GM type Orifice Pulse Tube Cryocooler P B Gujarati1, K P Desai1, H B Naik1 and M D Atrey2 1S V National Institute of Technology, Surat, Gujarat, India, 395007 2Indian Institute of Technology Bombay, Mumbai, Maharashtra, India, 400076 158-C1PoA New Model Capabilities Various analysis and Design models Enthalpy Flow analysis Phasor Analysis Isothermal Model Numerical Model Finite Volume Method (Discretization) Gauss Siedel Iterative Method Pressure and Temperatures (Node of a cell ) Mass flow rate /Velocity (Face of a cell ) Second Order Upwind Scheme (Advection terms) Assumptions in Numerical Model 1D flow of compressible helium gas No axial conduction in solids Pressure drop is neglected everywhere Transient Numerical Model Estimates the cool down behavior Uses the Conservation laws Higher accuracy in solution Rotary valve is an integral part of the model Model can calculate the pressure waveform Model can predicts the change in pressure ratio Energy Equation for Gas Outlet mass flow rate: Orifice Energy Equation for Solid Inlet mass flow rate: Rotary Valve For Pressurization For P > Pr Left end, Temperature boundary Uses mass balance at a given instant of time to calculate the pressure Temperature field is calculated from Energy equation of gas Tb=Tin for ṁleft ≥ 0 (left to right flow) Tb=Tgas for ṁleft < 0 (right to left flow) For P < Pr For Depressurization Right end, Temperature boundary Continuity Equation Tb=Tgas for ṁright ≥ 0 (left to right flow) Tb=Tr for ṁright < 0 (left to right flow) INPUT DATA Conclusion: The novel simulation model of orifice pulse tube cryocooler is proposed. The unique feature of the proposed model is that instead of fixed pressure waveform as pressure input to the numerical model, the present model is capable of calculating the pressure waveform from flow area variation between stator and rotor. This makes the model capable of designing and simulating the complete GM type pulse tube cryocooler including rotary valve. The model also predicts the change in pressure ratio during the cooldown process. The change in pressure ratio can be prevented to some extent by changing the valve timing diagram by proving different intake time. Better cooling performance can be achieved by optimizing the rotor by simulating the effect of different intake time. Stator - Rotor Geometry Pressure Ratio Variation Vs Cooling Time Refrigeration Power Parameters Value Length of Regenerator 210 mm ID of Regenerator 16.5 mm Length of Pulse Tube 230 mm ID of Pulse Tube 15 mm Wall thickness (Pulse Tube & Regenerator) 0.5 mm High Pressure 20 bar Low Pressure 8 bar Regenerator Mesh size SS 200 # Regenerator Porosity 0.68 Waveform Comparison % Change of Pressure Ratio Area variation at Rotary valve for different cases Change in Waveform Validation Cycle No Case-1 Case-2 Case-3 1 2.5 2.500 100 2.467 2.489 2.490 200 2.410 2.475 2.482 400 2.228 2.376 2.420 600 2.135 2.259 2.317 800 2.123 2.225 2.279 Steady State 2.120 2.226 2.276 % change 15.20 10.96 8.95 References: [1] Gifford W E and Longsworth R C 1964 Pulse tube refrigeration Trans. ASME. 86 264-8 [2] Mikulin E I, Tarasov A A and Shrebyonock M P 1984 Low temperature expansion pulse tube Adv. in Cryo. Engg. Plenum Press 29 629-37 [3] Zhu S, Wu P and Chen Z 1990 Double inlet pulse tube refrigerator-an important improvement Cryogenics 30 514-520 [4] Wang C, Wu P Y and Chen Z Q 1992 Numerical modelling of an orifice pulse tube refrigerator Cryogenics 32 785-90 [5] Wang C, Wu P Y and Chen Z Q 1994 Numerical analysis of double inlet pulse tube refrigerator Cryogenics 33 526-30 [6] Wang C 1997 Numerical analysis of 4 K pulse tube coolers: part I. numerical simulation Cryogenics 37 207-13 [7] Desai K P 2003 Investigations of orifice pulse tube refrigerator SVNIT PhD thesis 91 [8] Gujarati P B, Desai K P, Naik H B and Atrey M D 2015 Transient analysis of single stage GM type double inlet pulse tube cryocooler IOP Conference Series: Materials Science and Engineering Volume 101 article id. 012033 Case:1 (‘D’) Case: 2 (‘1.5D’) Case: 3 (‘2D’) Acknowledgement Authors are thankful to the Department of Science and Technology (DST), Government of India, (No.SR/S3/MERC-008/2011(G)) for funding the research project under which present work is carried out. Presented at CEC-ICMC 2017, Madison, USA – July, 2017